Cns depressants
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Cns depressants






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Cns depressants Cns depressants Presentation Transcript

  • Central Nervous System Depressants
  • CNS Depressants
    • Sedatives
    • Drugs that have an inhibitory effect on the CNS to the degree that they reduce:
      • Nervousness
      • Excitability
      • Irritability
      • without causing sleep
  • CNS Depressants
    • Hypnotics
    • Calm or soothe the CNS to the point that they cause sleep
  • CNS Depressants
    • Sedative-Hypnotics—dose dependent:
    • At low doses, calm or soothe the CNS without inducing sleep
    • At high doses, calm or soothe the CNS
    • to the point of causing sleep
  • Sedative-Hypnotics: Barbiturates
    • First introduced in 1903, standard agents for insomnia and sedation
    • Habit-forming
    • Only a handful commonly used today due in part to the safety and efficacy of: BENZODIAZEPINES
  • Sedative-Hypnotics: Barbiturates
    • Four categories:
    • Ultrashort
      • mephobexital, thiamylal, thiopental
    • Short
      • pentobarbital, secobarbital
    • Intermediate
      • aprobarbital, butabarbital
    • Long
      • phenobarbital
  • Sedative-Hypnotics: Barbiturates
    • Barbiturates have a very narrow therapeutic index.
    • Therapeutic Index
    • Dosage range within which the drug is effective but above which is rapidly toxic.
  • Sedative-Hypnotics: Barbiturates
    • Mechanism of Action
    • Site of action:
      • Brain stem (reticular formation)
      • Cerebral cortex
    • By inhibiting GABA, nerve impulses traveling in the cerebral cortex are also inhibited.
  • Sedative-Hypnotics: Barbiturates
    • Drug Effects
    • Low doses: Sedative effects
    • High doses: Hypnotic effects (also lowers respiratory rate)
    • Notorious enzyme inducers
  • Sedative-Hypnotics: Barbiturates
    • Therapeutic Uses
    • Hypnotics
    • Sedatives
    • Anticonvulsants
    • Surgical procedures
  • Sedative-Hypnotics: Barbiturates
    • Side Effects
    • Body System Effects
    • CNS Drowsiness, lethargy, vertigo mental depression, coma
    • Respiratory Respiratory depression, apnea, bronchospasms, cough
  • Sedative-Hypnotics: Barbiturates
    • Side Effects
    • Body System Effects
    • GI Nausea, vomiting, diarrhea
    • Other Agranulocytosis, vasodilation, hypotension, Stevens-Johnson syndrome
  • Sedative-Hypnotics: Barbiturates
    • Toxicology
    • Overdose frequently leads to respiratory depression, and subsequently, respiratory arrest.
    • Can be therapeutic:
      • Anesthesia induction
      • Uncontrollable seizures: “phenobarbital coma”
  • Sedative-Hypnotics: Barbiturates
    • Drug Interactions
    • Additive effects:
      • ETOH, antihistamines, benzodiazepines, narcotics, tranquilizers
    • Inhibited metabolism:
      • MAOIs will prolong effects of barbiturates
    • Increased metabolism:
      • Reduces anticoagulant response, leading to possible clot formation
  • CNS Depressants: Benzodiazepines
    • Most frequently prescribed sedative-hypnotics
    • Most commonly prescribed drug classes
    • Favorable side effects
    • Efficacy
    • Safety
  • CNS Depressants: Benzodiazepines
    • Classified as either:
    • Sedative-hypnotic or Anxiolytic
    • (Medication that relieves anxiety)
  • CNS Depressants: Benzodiazepines
    • Sedative-Hypnotic Type
    • Long-Acting:
      • flurazepam (Dalmane), quazepam (Doral)
    • Short-Acting:
      • estazolam (Prosom), temazepam (Restoril),
      • triazolam (Halcion)
  • CNS Depressants: Benzodiazepines
    • Anxiolytic Type
    • alprazolam (Xanax)
    • chloridiazepoxide (Librium)
    • diazepam (Valium)
    • lorazepam (Ativan)
    • midazolam (Versed)
      • zolpidem (Ambien) and zaleplon (Sonata)
      • (nonbenzodiazepine hypnotic agents, share characteristics)
  • CNS Depressants: Benzodiazepines
    • Mechanism of Action
    • Depress CNS activity
    • Affect hypothalamic, thalamic, and limbic systems of the brain
    • Benzodiazepine receptors
  • CNS Depressants: Benzodiazepines
    • Drug Effects
    • Calming effect on the CNS
    • Useful in controlling agitation and anxiety
  • CNS Depressants: Benzodiazepines
    • Therapeutic Uses
    • Sedation
    • Sleep induction
    • Skeletal muscle relaxation
    • Anxiety relief
    • Treatment of alcohol withdrawal
    • Agitation
    • Depression
    • Epilepsy
    • Balanced anesthesia
  • CNS Depressants: Benzodiazepines
    • Side Effects
    • Mild and infrequent
    • Headache Drowsiness Dizziness Vertigo Lethargy Paradoxical excitement (nervousness) “Hangover effect”
  • CNS Depressants: Nursing Implications
    • Before beginning therapy, perform a thorough history regarding allergies, use of other medications,health history, and medical history.
    • Obtain baseline vital signs and I & O, including supine and erect BPs.
    • Assess for potential disorders or conditions that may be contraindications, and for potential drug interactions.
  • CNS Depressants: Nursing Implications
    • Give 15 to 30 minutes before bedtime for maximum effectiveness in inducing sleep.
    • Most benzodiazepines (except flurazepam) cause REM rebound and a tired feeling the next day; use with caution in the elderly.
    • Patients should be instructed to avoid alcohol and other CNS depressants.
  • CNS Depressants: Nursing Implications
    • Check with physician before taking any other medications, including OTC medications.
    • It may take 2 to 3 weeks to notice improved sleep when taking barbiturates.
    • Abruptly stopping these medications, especially barbiturates, may cause rebound insomnia.
  • CNS Depressants: Nursing Implications
    • Safety is important
      • Keep side rails up
      • Do not permit smoking
      • Assist patient with ambulation (especially the elderly)
      • Keep call light within reach
    • Monitor for side effects
  • CNS Depressants: Nursing Implications
    • Monitor for therapeutic effects
      • Increased ability to sleep at night
      • Fewer awakenings
      • Shorter sleep induction time
      • Few side effects, such as hangover effects
      • Improved sense of well-being because of improved sleep